1. Field of the Invention
The present invention relates to distribution through a communication network and, more particularly, to a distribution system for distributing an application to a user terminal in response to a request from a user, a distribution server and a distribution method thereof, and a distribution program.
2. Description of the Related Art
One example of a conventional application distribution system is recited in “Java(™) Networking Launching Protocol & API Specification (JSR-56)” published in December 2000 by Sun Microsystems. An application distribution system of this kind is a system for conducting centralized management of a plurality of applications by a server and distributing an application to a user terminal in response to a request from a user.
FIG. 11 is a block diagram showing an example of a structure of a conventional application distribution system. The entire structure is made up of a distribution server 40 having a function of distributing an application, user terminals 50-1 to 50-n and an information transfer device 60 such as a Web server for connecting the distribution server 40 and each of the user terminals 50-1 to 50-n through a network.
The distribution server 40 includes a user authentication unit 41 for authenticating a user, a program code management unit 42 for managing a program code (yet to be optimized) of an application to be distributed and a user data management unit 43 for managing a setting file and a data file of an application so as to be correlated with each user.
Each of the user terminals 50-1 to 50-n has the same structure and includes an application management unit 51 having a function of obtaining an application from the distribution server 40 and executing the same.
Thus structured conventional application distribution system operates in a following manner. FIG. 12 is a flow chart showing processing of the distribution server 40. With reference to FIG. 12, processing will be described which is conducted when accepting an application acquisition request form the user terminal 50-1.
First, the user authentication unit 41 of the distribution server 40 receives a message indicative of an application acquisition request from the application management unit 51 included in the user terminal 50-1 (Step 1201). The message is composed of, for example, a name of a requested application, a name of a user which certifies character of a user as a requesting source and authentication information such as a password.
The user authentication unit 41 authenticates the user using the authentication information included in the above-described message (Step 1202). When the authentication fails (NO at Step 1202), the unit 41 returns an error (Step 1206). When the authentication succeeds (YES at Step 1202), the user authentication unit 41 obtains a program code of an application specified by the above message from the program code management unit 42 (Step 1203).
Next, the user authentication unit 41 obtains, from the user data management unit 43, the user data such as a setting file and a data file which is owned by the authenticated user and corresponding to the application included in the above message (Step 1204).
Lastly, the user authentication unit 41 distributes the program code and the user data obtained at Steps 1203 and 1204 as one application to the user terminal 50-1.
The conventional technique employs a system of transferring program codes forming an application to a user terminal without modification, which results in transfer of codes that are included in the program code and will not be used on the user terminal as well to accordingly cause wasteful use of communication traffic.